Guide to Hatches in flooring

September 29, 2021

Which hatch should you choose?

What is the difference between hatch types?

As languages and dialects, different words and concepts are developed to name a hatch. Understanding the difference is not always easy. Here is a brief introduction:

Lowered hatches

means that the hatch, when installed, is flush with the floor surface – without any elevated details.

A slatted hatch is a lowered hatch. Slatted hatch is a term for a construction method – i.e. that the hatch is built up of a core material that is glued and attached to a metal plate on the top and bottom. The advantages of the slat construction are good ability for insulation both against cold and noise, but also constructions with good strength properties in combination with low weight.

A manhole or floor plate hatch is also folded into the deck and will, as completed, be flush with the upper edge of the finished floor.

Duct hatches are usually also lowered and flush with the finished floor.

Folded hatches

is normally mounted on top of a surface, and usually builds 5-15 cm above the surface. They are seldom strong (they stick up and make them unsuitable for driving over). The advantage of folded hatches is properties against penetration of surface water. They are therefore suitable for external installation, for example on roofs, over shafts, or manholes.

Hatches for concrete casting

Hatches for concrete casting are flexible solutions with the intent of recessing to the desired surface. The hatches are filled with concrete to achieve the load requirements, and it is important to remember that the strength is reduced if it is saved for, for example, paving stones. In such cases, it is important to choose a hatch with sufficient depth.

Hatches for concrete casting provide a robust and solid solution. For larger hatches, it is recommended to use a hatch lift or other device to lift out the hatch.

Read more about hatch lifts here

With over 50 different types of hatches in our standard stock, we probably have the market’s largest selection

To make it easier to choose the right hatch for your project, we have prepared the hatch assistant. This is a to-do list of the various moments it is important that you think through and find out before you order a hatch in the floor. The hatch assistant can be found at the bottom of this page.

Which surface should the hatchet have?

There are different requirements for the surface of a hatch in the floor. In some cases a non-slip surface is desired, in other cases it is desired that the hatch is as invisible as possible.

The surface of the hatch has an influence on the choice of hatch and in some cases also the height of the hatch. This must also be seen in connection with the load on the hatch.

You should ask yourself:

Are there surface requirements?

Should the surface be non-slip?

How is the floor around the hatch? Tiles, carpet tiles, coatings, parquet?

Is there a requirement for the hatch to have the same surface as the floor around?

For outdoor hatches, it may also be relevant to lay cobblestones in the hatch.

We have hatches that are suitable for all environments, but it is important that we choose a hatch that has the right load – also with the desired surface.

For example, a hatch for casting concrete has a classified load when it is completely filled with concrete. If the amount of concrete is reduced to make room for cobblestones, the load on the hatch will consequently also be reduced.

Load on hatch in flooring

Hatches in the floor can be exposed to different loads. It is therefore important to identify which load is relevant in your case.

  • A hatch in the basement floor will probably only be exposed to passenger traffic
  • In office premises, it is important to identify whether heavy pallet trucks can be used, or whether the load will only be limited to pallet trucks and passenger traffic.
  • Parking basements with a limited ceiling height will normally only be exposed to loads from cars.
  • Industrial and warehouse premises may be exposed to loads from heavier vehicles and trucks. Does the hatch have to be placed in the carriageway, or can it be placed outside, and thus dimensioned for a lower load? Normally, there is a connection between requirements for load and price.
  • Quays and airports can be exposed to heavy loads, and hatches must be dimensioned for this load.
  • Should the hatch be left outside? Will there be a danger of driving load, or will only snow load be dimensioning for the load?
  • Load on hatches in the floor is dimensioned in accordance with EN124: 2015. You can read more about the standard here (Norwegian).

The illustration below shows the different load classes in EN124.

Placement and density requirements?

Should the hatch be placed inside or outside?

Hatches installed outside will most often have requirements to be tight against water penetration. We have different solutions depending on the requirements.

  • Can the hatch build over the surface? In that case, a folded hatch is ideal for the purpose. It can withstand passenger traffic, and will not be able to be exposed to any load other than snow load and passenger traffic. Folded hatches are waterproof, also against surface water up to 8-10 cm water level.
  • Should the hatch be placed over pumps, stake points, or open sewers? An odor-proof hatch must be used. This has gaskets that seal between the frame and the hatch. In addition, the hatch is locked or screwed to the frame.
  • Does the hatch sit above, for example, a process plant with negative pressure? In this case, a hatch must be used which prevents false air from being sucked into the processing plant. Similar to odor-tight lids, the seal between the frame and the hatch will ensure sufficient tightness. Here are solutions that are both locked to the frame with a lock or screw, or that are loose in the frame. The choice of solution will depend on requirements for pressure density and operating frequency.
  • Should the hatch be mounted in a fire compartment? Fire-rated hatch must be used. This has both tightness against smoke and odor in addition to being fire resistant according to EI90.

What is important to remember when operating a hatch?

How often will the hatch be operated?

How often the hatch should be opened or closed is decisive for the level of equipment and the functions it should have. If it is to be operated several times a day, equipment such as hinges, gas springs, and lifting handles are absolutely necessary. If, on the other hand, it is to be operated infrequently, and only for certain needs, the level of equipment and auxiliary devices will be simpler. Furthermore, it is important to consider whether the hatch should be operated by one or more people, or possibly with an overhead crane or similar. We produce hatches with lifting and operating equipment.

When does the hatch or lid need hinges?

Whether the hatch should be hinged also depends on how often it is to be operated. If the hatch is to be operated frequently, hinges are an advantage. Hinged hatches can also be equipped with equipment area delimitation to avoid accidental fall into the opened hatch.

When is there a need for a safety grille?

The hatch should have a safety grille when the fall height is so great that there is a risk of personal injury. Sometimes the safety grille is also an insurance against locking out unauthorized persons. A safety grille will also help to secure inspections and enable, for example, flushing to take place in a safe manner without risk of personal injury. Our safety grilles are hinged or easily dismantled – to provide as safe use as possible.

These hatches are well equipped to meet HSE requirements. The hatches can also be used for other types of installations without any problem.

Lockable hatches?

In our view, all hatches that are mounted outdoors must be lockable. Either with a padlock, or other security measures against the outsider’s access.

Our folded hatches are prepared for padlocks as standard.

For hatches that require frequent operation, we recommend the use of a snap lock. This provides the necessary safety against unintentional use, but is at the same time easy to operate for the operator. When the hatch is closed, it will automatically lock. Lowered hatches – hatches that align with the floor – can in some cases also be equipped with a triangle or square lock.

Requirements for frequent inspection?

Some process installation requires frequent inspection. At the same time, we experience that these process plants have negative pressure, which means that inspection is desired without opening a hatch. Our dome solution provides a good opportunity for visual inspection without opening the hatch. Depending on the temperature in the process plant, we have dome solutions with both single- and two-layer domes, which prevent dew formation.

The underside of the dome frame can be equipped with lights for easier visual inspection.

If the dome is also to be used for flushing, these are equipped with a safety grille on the underside. This is hinged and can easily be hinged to the side when full opening is required.

Requirements for frequent inspection?

We experience that the size of a hatch is based on different needs and preferences. It is therefore important to clarify early:

  • Is there a requirement for the size of the light opening – i.e. free opening inside the frame of the hatch? Often there may be technical installations or process equipment that must be hoisted up via an open floor hatch.
  • Is there a restriction on site that lays down guidelines for what goals a hatch can have? In some cases, the recess in the surface – i.e. the area where the hatch is to be installed – has been completed. In such cases, this lays down guidelines for how large a hatch can be fitted.
  • The choice of fastening also affects the size of the hatch. For example, if the hatch is sanded/shaken in after the surface has been cast, sufficient space must be set aside for this between the recess in the surface and the external dimension of the hatch. If the hatch is to be mounted in the formwork and cast in together with the surface, this does not need to be considered.
  • Some hatches have brackets that build into the light opening. It is therefore important to obtain information for what is to be hoisted through the hatch to ensure that the brackets do not obstruct.
  • All floor hatches should rest on a shelf or angle around the entire recess. It is important that the height from the top edge of the shelf/angle to the top edge of the cover is sufficient – and adapted to the relevant hatch and its construction height.